Irene Adler: An American opera singer with a "soul of steel," Irene Adler was the only woman ever to outwit Sherlock Holmes, and is now determined to solve and avenge the mystery of his murder for the most personal of reasons.

 

Winfield Scott Lovecraft: A courageous silver seller from Providence who comes to Irene's aid, despite a private struggle of his own.

Mycroft Holmes: Sherlock Holmes' brilliant older brother and founder of the enigmatic Diogenes Club.

Dr. John Watson: Good-hearted and stalwart companion to Sherlock Holmes and a fast friend to Irene.

Wiggins: Young leader of the Baker Street Irregulars whose life is threatened by a secret.

Colonel Sebastian Moran: Iron-willed ex-soldier and hunter who holds the key to Sherlock Holmes' murder.

Ygor Barnabus: Sinister associate of the late Professor Moriarty who is pursuing an unthinkable occult agenda.